Life support system

ABSTRACT

A closed cycle HeO2 cryogenic underwater life support system is disclosed as including a breathing gas rejuvenation process, wherein helium gas is added thereto to maintain proper breathing gas pressures at various and sundry water depths, carbon dioxide and water are removed therefrom, and life-sustaining oxygen gas is added thereto from liquid oxygen cooled to cryogenic temperatures by means of a cryogenic chamber and refrigeration apparatus. Controlled heating equipment is also disclosed for the purpose of maintaining proper temperatures in said breathing gas rejuvenation process, as well as in a diver&#39;&#39;s suit. Excess nonrejuvenated gas is stored in a gas dumping container located within the cryogenic chamber, but may be vented to the ambient water environment should said gas dumping chamber become full.

United States Patent 11 1 1111 3,831,594 Rein 1 51 Aug. 27, 1974 LIFE SUPPORT SYSTEM on 112R P1 IBLICA'ITIONS [75] inventor: Charles R. Rein, Panama City, Fla. Design News, Vol. 15 July 21, 1969, 14'

[73] Assignee: The United States of America as represented by the Secretary of the Primary Examiner-Kyle L. Howell Navy, Washington, DC. Attorney, Agent, or Firm-Richarcl S. Sciascia; Don D.

22 Filed: Mar. 5, 1973 DOW; Harvey [21] Appl. No.: 337,782 57 ABSTRACT A closed cycle HeO cryogenic underwater life sup- [52] US. Cl 128/142, 62/48, 62/50, port system is disclosed as including a breathing gas 128/203, 165/46 rejuvenation process, wherein helium gas is added [51] Int. Cl A62b 7/06 thereto to maintain proper breathing gas pressures at [58] Field of Search 128/142, 142.2, 203; various and sundry water depths, carbon dioxide and 62/50, 52, 48; 165/46 water are removed therefrom, and life-sustaining oxygen gas is added thereto from liquid oxygen cooled to [56] References Cited cryogenic temperatures by means of a cryogenic UNITED STATES PATENTS chamber and refrigeration apparatus. Controlled heat- 3 366107 W968 Framom 178/147 2 ing equipment is also disclosed for the purpose of 128/1422 maintaining proper temperatures in said breathing gas 165/46 X rejuvenation process, as well as in a divers suit. Ex- 1 5 4 cess non-rejuvenated gas is stored in a gas dumping 128/ 1422 container located within the cryogenic chamber, but

3,370.585 2/1968 O'Neill 3,450,127 6/1969 Harwood. Jr. 3,556,205 1/1971 Harwood, Jr. 3.570.481 3/1971 Woodberry, lr..

3572.048 3/1971 Murphy 1 i 62/52 may be vented to the ambient water environment 3,707,078 12/1972 Cramer 62/50 h ld id gas d i h b become f ll 3.710.553 l/l973 Parker ct a1. 128/1422 X 3.714.942 2 1973 Fischel et al 128/203 x 16 m 1 r ing F g r l6 14 ,15 ls 12 OUT 3 IN H MAKE MAN. MAKEUP MOUTH up PASS BREATH CHECK PIOERCE CHECK w BREATH HWUM VALVE VALVE BAG VALVE HABITAT VALVE BAG ii i l w n w w Q .-.J 1 66 38 M h t a l m 1 12 r" PUMPED lI'IVER HEATED BREATH I ExcEss I WATER SUIT C02 GAs HEAT HEATER QT SCRUBBER HEATER EXCH. l l l l l l WATER {37 49 FT 7'9 2| l ENX.

PRESS PRESS I PRESS CONTROLLED RELIEF DESSICANT COOLER RELIEF VALVE VALVE I VALVE l H WATER ENVIRONMENT 45 48 PRIMARYHEAT 22 EXCHANGER e2 43 E46 as 25 l l I i I SECONDARY 1.

HEAT 5 1 6| EXCHANGER 592k 534 f CRYDGENIC CONTAINER FOR He 02 BREATHING GAS MIXTURE POWERED 1 REFRIGERATOR 46 PRESS. l CONTROL EXCESS I VALVE GAS 1 WATER DUMPING I ENVIRONMENT CONTAINER I CHECK L VALVE PATENTED AUG 2 71974 6 5' OUT 3 IN N 5 4 MAKE- MAN. MAKE-UP j C ECK MOUgH CHCK BREATH H PIE E BREATH up BYPASS CONT BAG VALVE R VALVE BAG HELIUM VALVE VALVE I HABITAT I i T T I j r J 1 R V J I V f' I 7 1 7 PUMPED DIVER HEATED BREATH I ExcEss t2 wATER cog GAS 1 HEAT HEATER HABITAT SCRUBBER HEATER EXCH.

I L l l l I wATER 37 49 I ENv. f \c I I 5' 4 I PRESS PRESS 1' PRESS CONTROLLED RELIEF DESSICANT COOLER RELIEF VALVE VALVE VALVE I A A wATER ENVIRONMENT 45 48 PRIMARYHEAT 22 4 36 EXCHANGER 62 4 s5 25 l J i I SECONDARY HEAT sI EXCHANGER 59 \I $34 CRYOGENIC CONTAINER FOR He 02 BREATHING GAS MIXTURE 52 \l" POWERED 40 REFRIGERATOR 4 PRESS- 47K CONTROL EXCESS I VALVE GAS I WATER A D I ENvIRoNMENT coNTAINER l CHECK 3g VALVE I l LIFE SUPPORT SYSTEM STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

1. Field of the Invention The present invention relates, in general, to life sup port systems which provide an atmosphere of breathable gas within an environment which would otherwise be too hostile for humans and other air breathing mam mals to live and perform useful functions for any reasonable period of time. In particular, it is a closed cycle cryogenic system for producing and supplying a breathable gas mixture to human swimmers and divers operating under water and also to various and sundry compatible under sea habitats.

2. Description of the Prior Art Heretofore, numerous life support systems have been available to scuba divers and underwater habitats. Ordinarily, pressurized tanks of oxygen and other gases are carried by the diver and selected mixtures thereof are breathed thereby. Although satisfactory for some purposes usually those associated with water sports a great deal is to be desired if the diver wishes to keep his presence at some subaqueous location a secret. This is true because most scuba systems release the divers exhaled breath to the ambient water, thereby causing visible bubbles to betray his presence. Moreover, all known prior art deep diving scuba systems require that part of the gaseous breathing mixtures be vented to the ambient water on momentary ascent a procedure which also betrays the presence of the diver.

SUMMARY OF THE INVENTION The instant invention overcomes many of the disadvantages, either directly or indirectly, associated with the prior art, in that it consists of a plurality of interacting subsystems which not only prevent the betrayal of the location ofthe diver but also enable him to operate at relatively great water depths with a minimum of discomfort, considerably more of which would otherwise be encountered due to his having to breathe underwater at said depths, and due to his exposure to the low temperatures located thereat. In other words, it is a new and unique life support system which facilitates the divers working efficiently and safely at considerable water depths in a covert manner.

Therefore. it is an object of this invention to provide an improved life support system for swimmers, divers, underwater habitats, and the like.

Another object of this invention is to provide an improved helium-oxygen gaseous mixture suitable for breathing by humans or other air breathing beings at great water depths for long periods of time.

Still another object of this invention is to provide a new and unique closed cycle. long-lived. cryogenic life support system adapted for being used in hostile ambient environmental mediums, such as, for example, in water, sea water, space, contaminated atmospheres, and the like.

A further object of this invention is to provide a method and means which enables a diver to work safely, efficiently, and comfortably at great water depths without betraying his presence.

Still another object of this invention is to provide an improved method and means for producing and maintaining predetermined breathable mixtures of helium and oxygen at various and sundry environmental locations useful to man and other air breathing mammals.

A further object of this invention is to provide an improved method amd means for producing and maintaining predetermined mixtures of certain inert or other gases with oxygen at useful environmental loca tions.

Another object of this invention is to extend the time and water depth at which a free diver may operate over those provided by the known prior art, thereby enabling him to work and otherwise perform useful functions for, say, as long as 6 hours and of water depths of approximately 1,000 feet.

Still another object of this invention is to provide a method and means for controlling the partial pressure of oxygen as a result of regulating the temperature of liquid oxygen (LOX).

Another object of this invention is to provide a new and unique apparatus combination for supplying heated, CO scrubbed, breathable helium-oxygen gaseous mixtures to heated diver suits, habitats, and the like without electronic controls being required.

Still another object of this invention is to provide an improved closed cycle cryogenic scuba system which permits the breathing gas processing loop thereof to remain at the pressure of the ambient water environment on the momentary ascent of a diver located therein without release of gas thereto.

Other objects and many of the attendant advantages will be readily appreciated as the subject invention becomes better understood by reference to the following detailed description, when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1, the sole FIGURE in this case, illustrates in combined block diagram and mechanical schematic form the closed cycle cryogenic life support system constituting the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT At the outset, it should perhaps be reiterated for the purposes of clarity and simplicity of disclosure that the preferred embodiment of the invention about to be described is depicted in such manner that the various and sundry conventional components thereof are indicated by blocks with legends, and that the lines respectively drawn therebetween represent pipes which allow the passage of gases or other fluids therethrough.

Referring now to FIG. 1, the life support system constituting this invention is shown as containing a conduit means or mouth piece 11 of the type used by an underwater swimmer or diver for the purpose of inhaling lifesustaining gas therefrom and exhaling CO and H 0 contaminated breath thereto.

Although the instant embodiment of the subject invention is primarily intended for people actually swimming and diving under water, it should be understood at the outset that its use is not limited thereto and, thus, it may be combined with other suitable habitats, chambers, or the like, for the purpose of supplying lifesupporting or other gaseous mixtures thereto. Of

course, said mouth piece 11 and many of the components combined therewith would have to be designed for the particular purpose intended and for making it compatible with any other equipment associated therewith, if it is to operate in an optimum manner. However, so doing would be well within the purview of one skilled in the art having the benefit of the teachings presented herewith.

The downstream, exhaled breath output of conduit or mouth piece 11 is connected to the input of a one way check valve 12, the output of which is connected to the downstream input of a resilient, flexible exhale breathing bag 13. A helium or other suitable diluent gas make-up valve 14 is mechanically connected in this particular embodiment in such manner that when bag 13 changes in configuration due to collapsing a lever or other mechanical linkage 15 is adjusted in position, thereby causing control valve 14 to open and allow helium or said other suitable diluent gas to pass therethrough. Of course, said helium gas is supplied to control valve 14 because the output of a pressurized makeup helium container 16 is connected to the input thereof.

A manually operated by-pass valve 17 is connected between the output of make-up helium container 16 and the interconnected outputs of control valve 14 and breathing bag 13. As a result of such connections, it may readily be seen that the outputs of breathing bag 13, make-up control valve 14, and by-pass valve 17 are all connected to the input of a heated carbon dioxide (CO scrubber 18. The gas output of heated CO scrubber 18 is connected to the input ofa container of dessicant 19 (such as, for instance, silica gel or a molecular sieve), the output of which is connected to the input of a gas cooler 21, the latter of which is in heat exchange contact with the ambient environmental medium.

The output of cooler 21 is connected to a giving-up heat" or cooled passage 22 of a primary heat exchanger 23 located within a cryogenic container 24 but effectively insulated therefrom.

At this time, it might be well to note that any suitable cryogenic container or chamber may be employed cryogenic container 24. Moreover, any appropriate conventional means may be employed to cool container 24 to cryogenic temperatures. For example, entire cryogenic chamber 24 may, immediately prior to being used in the subject life support system, be inserted in a suitable chest-type cryogenic refrigerator for cooling purposes. Then, when it has cooled to the proper temperature internally, it is withdrawn from said refrigerator chest and used as intended. On the other hand, if so desired, a cooling coil may be inserted within chamber 24 and supplied with liquid nitrogen or I some other cooling fluid from an external source until chamber 24 has cooled to the proper cryogenic temperature. Once such temperature is reached, the external cooling fluid source is manually disconnected from said cooling coil and, hence, from container 24, as well and then cryogenic chamber 24 is used in its normal manner in the subject system.

Obviously, as will be mentioned again subsequently, many well known, conventional refrigeration systems (including those mentioned above) could be readily adapted to this invention for cryogenic cooling purposes by the artisan, so it will not be belabored any further at this time.

The output of cooled passage 22 of primary heat exchanger 23 is connected to a cooled input 25 of a secondary heat exchanger 26, the cooled output 27 of which is connected to another cooling heat exchanger, such as coil 28, disposed within a pool of liquid oxygen 29 located within a container 31 in such a manner as to fill it sufficiently to cover said cooling coil 28 but not so full as to prevent a chamber of oxygen gas (0 32 from existing above the surface of liquid oxygen 29. Of course, said oxygen gas 32 occurs as a result of the boiling off the surface of the aforesaid liquid oxygen 29 within container 31.

Extending as a pressure sensing element within the oxygen gas filled portion 32 of chamber 31, is an openended pipe 33, the other end of which is connected to a warmed input 34 of secondary heat exchanger 26. The output 35 thereof is connected to the input of a warmed or heated passage 36 located within primary heat exchanger 24, with the output thereof connected through a water heater pressure controlled valve 37 to the fuel combustion chamber of a powered pump type water heater 38.

As may readily be seen, pressure controlled valve 37 senses the pressure within the oxygen gas supplied to it and, therefore, it has a pressure sensor connection therewith for such purpose. In addition, pressure controlled valve 37 may optionally be of the type which may be manually adjusted, so that the pressure in supply line 35, which causes it to open, is proportional to said manual adjustment. As a result of such 0 pressure control procedures being effected by pressure controlled valve 37, the heat produced by water heater 38 is proportional to the amount of oxygen which is boiled off from LOX supply 29. This, of course, is proportional to the heat transferred to LOX supply 29. And the more O- supplied to the heater, the more heater fuel that is burned and, hence, the more heat that is produced thereby.

In order to prevent the necessity of exhausting gaseous products of combustion from water heater 38 to the ambient water environment, a suitable conventional fuel that prevents the production thereof should be used in heater 38. For example, such fuels as magnesium and phosphorus may be used for such purpose, since they both form a solid product of combustion when burned with oxygen gas.

Output 27 of secondary heat exchanger 26 is also connected through a pressure controlled valve 40 to the input of a check valve 41. The output of check valve 41 is connected to an excess gas dumping container 42, the output of which is connected to the input of another "take-up heat" or heated passage 43 located in primary heat exchanger 23. Pressure controlled valve 40 is of the automatic control type which can be set for controlling at some given pressure difference between the gas from secondary heat exchanger outlet 27 and the ambient environmental medium in this case, water 45. In order to sense such pressure differential, sensors 46 and 47 are connected as shown to pressure controlled valve 40.

The output of coil 43 is connected to the input of a pressure relief valve 48 which may be set to exhaust to the water environment whenever the pressure in container 42 exceeds its design pressure.

Another pressure relief valve 49 is connected to the output of the aforesaid breathing bag 13 for venting the gas thereat to water environment 45, in the event its pressure exceeds that of the ambient water by a predetermined amount. Optionally, pressure relief valve 49 could be put elsewhere in the breathing gas loop.

The output of the aforementioned cooling coil 28 disposed in liquid oxygen 29 in container 31 is connected to the input of a stand pipe 51 extending from the bottom of a container 52. Surrounding standpipe 51 is another standpipe 53 having a plurality of holes or apertures 54 in the wall thereof at or near the upper end thereof. A predetermined amount of liquid oxygen (LOX) 55 is disposed in container 52 in such a manner as to partially fill it and also partially extend around the lower, non-apertured portion of standpipe 53. A wick 56 having a closed end 57 is securely hung around the outside of standpipe 53 in such manner as to completely cover apertures 54 and extend down into liquid oxygen 55. Above the surface of liquid oxygen 55 but within chamber 52 is a volume of helium and oxygen mixture 58 constituting HeO breathing gas.

The output of the compartment of chamber 52 containing said HeO gas is open by means of a predetermined vent pipe 59 to the entire inner chamber 61 of cryogenic container 24, and said inner chamber 61 is also in communication with the input of the taking-up heat" or breathing gas heat exchanger passage 62 located in the aforesaid primary heat exchanger 24.

At this time, it would perhaps be noteworthy that excess gas dumping container 42 and chamber 52 are separated'by but connected to chamber 31. Also, it should be noted that all three thereof are very cold for several reasons: (1) chambers 31 and 52 contain liquid oxygen, a very cold substance; (2) all three, being connected together in a heat conductive manner, tend to act as heat sinks, respectively. and thus reach a temperature equilibrium near the temperature of liquid oxygen; and (3) all three are located within cryogenic container 24, itselfa very cold chamber. Because excess gas dumping container 42 is very cold, it will hold considerably more excess gas than it would ifit were at ambient water temperature. This will prevent the necessity of venting excess breathing gas to the ambient water every time the diver ascends for some reason or another until the pressure in container 42 equals the ambient water pressure. This, in turn. allows the diver to operate covertly under water. if he so desires.

The output of coil heat exchanger passage 62 is connected to the input of a breathing gas heater 63, the breathing gas output of which is connected to the input of a resilient. inflatable inhaling breathing bag 64. The output of breathing bag 64 is connected through check valve 65 to the upstream input of the aforesaid mouth piece 11 for supplying breathable H802 thereto and via the out-in portion thereof to the diver (not shown).

As may readily be seen, the portion of the subject invention discussed so far constitutes the closed breathing gas loop and several pressure and temperature controls therefor. In addition. there is an equipment heating loop, of which the aforesaid water heater 38 is a part. This heating loop is, of course, a closed loop of several components of the invention. some of which are directly connected thereto and some of which are indirectly associated therewith.

Water heater 38 contains a heated water passage 86 (including, for example, a battery powered pump for pumping heated water therethrough and to other heated units of the invention) which is connected in parallel by passage 67 of diver suit (or habitat) 68, passage 69 of CO scrubber l8, passage 71 of breathing gas heater 63, and passage 72 of an excess heat exchanger 73, the latter of which is disposed for transferring excess heat to ambient water environment 45, like the aforesaid cooler 21.

Of course, as previously suggested, depending on the circumstances involved and the nature of the environmental medium concerned, any other appropriate container, housing, unit, device, habitat, or the like, may be substituted for diver unit 68 for any given operational purposes or added on to the hot water loop.

In the event a habitat is substituted for mouth piece 11, it may, if desired, be substituted for diver suit 68, too, and thus be heated by the hot water from pumped water heater 38. To show such habitat in its proper relationship with its associated components, a dashed line is shown interconnecting elements 11 and 68.

Numerous possible alternate arrangements may be made in the instantly disclosed invention by the informed artisan without violating the spirit or scope thereof. For instance, any or all fluids enroute to the cryogenic section may be put in thermal contact with any or all fluids being removed from the cryogenic section. The primary and secondary heat exchangers may be combined into one heat exchanger. Sometimes, depending on operational conditions, the breathing gas cooler can be eliminated or combined with or placed upstream of the dessicant canister. Furthermore, the evaporation rate of the heater LOX may be held above a set minimum value by installing an additional controlled heat leak to the cryogenic section. The heat applied to the CO scrubber could be recovered from the breathing gas flowing out of it by gas flowing to the breathing gas heater or to the mouth piece. Although the system of the disclosed preferred embodiment assumes that CO and water are to be removed by conventional heated or unheated scrubbers, said CO and water could be solidified in a heat exchanger or somewhere in the cryogenic section. Although the use of pumps in one or both of the fluid circulation loops is probably desirable, with the power therefor being electrical, pumping could be effected manually or by a simple heat engine operated by the excess heat or by other means. A breathing gas regenerator could be substituted for the breathing gas heater, if so desired. Control of the volume of the breathing gas could be effected by the motion of a bellows or other pumping device in the breathing gas loop, as well as by the pressure difference between the breathing gas and the water. And, moreover, in operations where heat is not required, the cryogenie coolant could be a substance which evaporates or melts to take up heat. The heating apparatus would then be eliminated from the subject system, but bubbleless performance would still be possible.

Obviously, one skilled in the art having the benefit of the teachings presented herewith could make the aforementioned system and perhaps other design choices and changes which would result in any other preferred embodiment of the invention warranted by operational and environmental circumstances.

Because container 24 is a cryogenic container for the HeO- breathing gas mixture and the other apparatus shown in FIG. 1, it becomes necessary to cool it to and maintain it at cryogenic temperatures. Several conventional procedures and devices, as previously suggested, may be used for such purpose. For example, cryogenic container 24 may be put into a refrigerated chest and cooled to the desired temperature just before it is to be used by a diver. Of course, under any circumstances. the walls of container 24 must be exceedingly good insulators. in order to prevent an inordinant amount of deleterious heat transfer from occurring between the outside ambient environmental medium and the inside thereof. For some practical applications, a Dewar might be used as container 24', on the other hand, for many other practical applications, it would be preferable for container 24 tohave its own refrigerator equipment, so thatit would be self-contained, so to speak. Accordingly, by way of example and without any limitation intended, a powered refrigerator 75 the power supply of which may be either internal or external is depicted as being mounted within cryogenic container 24 for the purpose of cooling it to and essentially maintaining it at cryogenic temperatures.

If so desired, pressure, temperature, and other parameters may be monitored at various and sundry locations within the subject system. For such purpose, test points may be optionally incorporated anywhere therein by the artisan. In addition, appropriately disposed flll lines may be included necessary to replace all of the fluids in the system.

MODE OF OPERATION The operation of the invention will now be discussed briefly in conjunction with the sole FIGURE of the drawing.

As previously indicated, the invention is primarily intended for supporting life within deep water and to do it in such manner that gas does not have to be vented to the ambient water, even during momentary ascension, and provides, as an additional benefit, thermal protection for divers in cold waters.

Referring now to FIG. 1. it may be seen that the subject system comprises several interactive, either directly or indirectly, gas flow piping loops or circuits. Beginning with mouth piece 11 ofthe first loop or subsystem which, of course, is partially inserted in the mouth of a diver (not shown), an in-out member is symbolically disclosed in connection therewith as means for receiving the divers exhaled breath and supplying the divers inhaled breath, respectively. When. for example, the diver has exhaled into mouth piece 11, it passes through one-way check valve 12 into breathing bag 13, thereby expanding it. Of course, the divers exhaled breath does not travel to breathing bag 64 because it is stopped by one-way check valve 65. With each exhaled breath, bag 13 expands somewhat, and with each inhaled breath bag 13 collapses somewhat. Normal breathing should keep bag 13 filled some minimum amount at all times; however, if due to descent of the diver or for some other reason the inflation of bag 13 is not maintained at said minimum level, the physical position thereof becomes such that lever 15 is moved, thereby opening up make-up valve 14 sufficiently to allow some helium from pressurized make-up helium container 16 to pass therethrough and into the exhaled gas exit line of breathing bag 13.

At this time, it may be noteworthy that, in the event make-up valve 14 does not work properly, the diver could manually open by-pass valve 17 and produce the same result, namely, supply more helium to the output line of bag 13.

The exhaled breath of a diver, of course, contains an excess quantity of carbon dioxide (CO gas as well as water vapor (H 0) and a reduced amount of oxygen (O gas, for further life support purposes. Hence, the exhaled breathing gas is scrubbed to remove said CO in heated scrubber 18, after which it is passed through dessicant canister 19 to remove the moisture therefrom. After removal of the moisture therefrom, the exhaled gas is cooled to the temperature of the ambient water by natural convection cooler 21; however, if desired, in some cases, the exhaled gas may be cooled be fore it is dried in the dessicant. Next, the exhaled gas is cooled to cryogenic temperatures by passing successively through primary heat exchanger 24, secondary heat exchanger 26, and cooling coil 28 located in liquid oxygen (LOX) 29. After being so cooled, the exhaled gas passes up through standpipe 51, through standpipe holes 54, and through oxygen saturated wick 56, where it, too, becomes saturated with oxygen in HeO chamber 58 above the surface of LOX 55.

At wick 56, the exhaled gas again attains the proper partial pressure of 0 for life support at a diver, so from here on, it will be known as the inhalable gas, although several other operations are still to be performed on it.

From chamber 58, the inhalable gas passes through cryogenic container 24, through heater coil 62 of primary heat exchanger 23, gas heater 63, expandable breathing bag 64, and check valve 65 before being returned to mouth piece 11. Of course, breathing bag 64, like downstream breathing bag 13, is desirable at the disclosed position upstream of mouth piece 11.

As suggested in brief above, a gas flow subsystem is employed for supplying helium gas to the downstream exhaled gas whenever bag 13 is too collapsed, as a result of loss of gas volume in the aforementioned first loop. In spite of variations in pressure, the actual volume of the breathing gas must be held approximately constant, so when, for example, the diver descends to a greater water depth, helium from make-up helium container 16 flows into loop one, the breathing gas loop, to maintain the actual breathing gas volume, thereby allowing the diver to fill his lungs with each breath. It would appear to be especially noteworthy at this time, that the helium is injected into the downstream or exhale region of the breathing gas, so that helium make-up occurs without significant change in the partial pressure of oxygen in the inhaled gas.

The third subsystem performs the gas volume regulation during the ascent of the diver, thereby preventing venting of gas to the water. On ascent, the breathing gas is vented to excess gas dumping container 42 where it is stored at the same temperature as LOX 29. Storage of said gas at such temperature, as previously implied, permits storage of gas in approximately one third the volume that otherwise would be necessary if the gas were stored at ambient temperature.

Actual regulation of the aforesaid excess brathing gas during ascent is effected by pressure controlled valve 41. If the gas pressure of effluent 27 of secondary heat exchanger 26 becomes significantly greater than that of ambient water environment 45, sensors 46 and 47 sense the pressure difference therebetween and open valve 41, thereby venting some of the exhaled breathing gas into container 42, rather than sending it on through cooling coil 28 incontainer 31. As a general rule, to facilitate such gas dumping, excess gas dumping container 42 should be evacuated at the beginning of the dive.

When the breathing gaseous mixture is vented to the excess gas dumping container, there is no corresponding counter flow through the primary and secondary heat exchangers, and, thus, an increase in the boil-off rate of water heater temperature control LOX 29 must occur. The evaporated oxygen gas is not released to the water, however, but, instead, flows through the fourth flow subsystem to water heater 38, where it reacts with the heater fuel. Since said heater fuel is magnesium, phosphorus, or other appropriate fuel which does not produce gaseous products of combustion when combined with oxygen, no material discharge from water heater 38 to ambient water environment 45 is necessary. Of course, as a result of no discharge occurring from heater 38, the excess heat produced thereby must be transferred to water 45 by excess heat exchanger 73. The net result of such procedure, then, is that the divers ascent causes heat to be given off to water 45 instead of gas bubbles. Of course, this is a welcome trade for any diver who desires to avoid detection.

The fifth loop or subsystem is a liquid loop that carries the heat produced by water heater 38 to diver suit 68 and breathing gas heater 63. Also, as indicated, CO scrubber l8 may be heated in such manner that it will provide optimum scrubbing operations. Excess heat exchanger 73 is, of course, necessary in order to transfer excess heat to ambient water 45 whenever heater LOX 29 boil-off rate causes heater 38 to produce more heat than the other heated components require. If so desired, said components which require heat may also incorporate their own individual internal thermostats. The pressure of heater LOX 29 is effectively regulated at the entrance side of heater 38 by pressure controller 37. If the pressure in water heater LOX chamber 31 is so controlled, the temperature of LOX 29 and the rest of the cryogenic section will also be properly controlled, Thus, the partial pressure M in the breathing gas is properly controlled, thereby effecting an optimum HeO- gaseous mixture for diver breathing purposes. regardless of the water depth at which he is working.

From the foregoing, it may readily be seen that exceedingly worthwhile results are produced by the new and unique life support system constituting this invention, and that the above mentioned objectives thereof are fully met thereby.

Obviously. other embodiments and modifications of the subject invention will readily come to the mind of one skilled in the art having the benefit ofthe teachings presented in the foregoing description and the drawing. it is, therefore, to be understood that this invention is not to be limited thereto and that said modifications and embodiments are intended to be included within the scope of the appended claims.

What is claimed is:

l. A system for supporting life in a predetermined en vironment. comprising in combination:

respiratory means having a unitary input-output for receiving the exhaled breath of and for supplying a predetermined breathable, life-sustaining, gaseous mixture to an ordinarily air-breathing being, a downstream exhaled breath output. and an upstream inhalable gas input;

a first check valve, adapted for free downstream flow, connected to the downstream exhaled breath output of said respiratory means;

a first resilient, inflatable breathing bag having an input and an output, with the input thereof connected to the output of said [first check valve;

means connected to the output. of said first resilient,

5 inflatable breathing bag for removing carbon dioxide gas from the exhaled gaseous breath passing therethrough;

means connected to the output of said carbon dioxide gas removing means for removing the moisture from the exhaled gaseous breath passing therethrough;

means connected to the output of said moisture removing means for cooling the exhaled gaseous breath passing therethrough to the temperature of said predetermined environment;

means effectively connected to the output of said carbon dioxide gas removing means for adding a predetermined quantity of gaseous oxygen to the exhaled gaseous breath passing therethrough at a predetermined partial pressure from a reservoir of liquid oxygen disposed within a cryogenic container;

means connected to the output of said gaseous oxygen adding means for warming the gaseous breath to which said gaseous oxygen was added to a temperature which facilitates the breathing thereof by said ordinarily air-breathing being;

a second resilient. inflatable, breathing bag having an input and an output, with the input thereof connected to the output of said oxygen-added gaseous breath warming means;

a second check valve, adapted for allowing free downstream flow, connected between the output of said second resilient, inflatable bag and the upstream inhalable gas input of said respiratory means;

a container of pressurized predetermined make-up breathable gas;

a make-up control valve, adapted for being opened in proportional response to predetermined inflation conditions of said first breathing bag, connected between the output of said predetermined makeup breathable gas container and the input of the aforesaid carbon dioxide gas removing means; and

a manually operable by-pass valve connected in parallel with said make-up control valve.

2. The system of claim 1, wherein said respiratory means comprises a divers mouthpiece.

3. The system of claim 1, wherein said respiratory means comprises a habitat for air-breathing beings disposed within said predetermined environment.

4. The invention of claim 1, furthercharacterized by:

a controllable water heater having a pump incorporated therein in such manner as to pump heated water out the output thereof;

a diver suit connected to and downstream of said controllable water heater in such manner as to be heated a predetermined amount by the pumped heated water therefrom;

means connected to and downstream of said water heater for heating said carbon dioxide removing 6 'means a predetermined amount by the pumped heated water therefrom; means connected to and downstream of said water heater and pump for supplying a predetermined amount of heated water to said gaseous oxygenadded breath warming means for effecting the proper warming thereof; and

an excess heat exchanger connected to and downstream of said water heater and pump for transferring excess heat in the pumped heated water to said predetermined environment.

5. The invention of claim 1, further characterized by:

a controllable water heater having a pump incorpo' rated therein in such manner as to pump heated water and the output thereof;

habitat means which enables human beings and other air-breathing mammals to live and perform useful functions in an otherwise unlivable environment connected to and downstream of said controllable water heater in such manner as to be heated a predetermined amount by the pumped heated water therefrom;

means connected to and downstream of said water heater and pump for heating said carbon dioxide removing means a predetermined amount by the pumped heated water therefrom.

means connected to and downstream of said water heater and pump for supplying a predetermined amount of heated water to said gaseous oxygenadded breath warming means for effecting the proper warming thereof: and

an excess heat exchanger connected to and downstream of said water heater and pump for transferring excess heat in the pumped heated water to said predetermined environment.

6. The system of claim I, wherein said means connected to the output of said carbon dioxide removing means for removing the moisture from the exhaled gaseous breath passing therethrough comprises a canister of dessicant.

7. The system of claim 6 wherein the dessicant of said canister of dessicant comprises silica gel.

8. The system of claim 1, wherein said means effectively connected to the downstream exhaled breath output of said respiratory means for removing carbon dioxide gas from the exhaled gaseous breath passing therethrough comprises a heatable carbon dioxide gas scrubber.

9. The invention of claim 8. further characterized by means connected to said carbon dioxide gas scrubber for the heating thereof to a predetermined temperature.

10. The system of claim 1, wherein said means effec tively connected to the output of said carbon dioxide removing means for adding a predetermined quantity of gaseous oxygen to the exhaled gaseous breath passing therethrough at a predetermined partial pressure from a reservoir of liquid oxygen disposed within a cryogenic container comprises:

a primary heat exchanger having a plurality of heating passages and a cooling passage;

a secondary heat exchanger having a heating passage and a cooling passage, with the input ofthe cooling passage thereof connected to the output of the cooling passage of said primary heat exchanger;

an elongated container having a first self-contained container section at one end thereof with a predetermined vent in the wall thereof, a second selfcontained container section at the other end thereof, and a third self-contained container seetion located between said first and second selfcontained container sections, said first, second, and third self-contained container sections being in heat sink configurations with each other, respectively;

a first open-ended standpipe located within said first self-contained container section and extending a predetermined distance from the wall thereof that is opposite the vent thereof;

a second standpipe located within said first selfcontained container section, disposed around said first standpipe, and extending a greater distance from said wall than said first standpipe, said second standpipe having one end thereof closed by said wall and a plurality of apertures through the wall thereof in proximity with the other end thereof;

a first quantity of liquid oxygen partially filling said first self-contained container section in such manner that it surrounds a predetermined length of said second standpipe without passing through a plurality of apertures through the wall thereof;

a wick mounted on said second standpipe and dipsosed therearound in such manner as to be partially submersed in said first quantity of liquid oxygen;

a second quantity of liquid oxygen partially filling said third self-contained container section;

a cooling passage, having an input and an output, disposed within said second quantity of liquid oxygen, with the input thereof connected to the output of the cooling passage of the aforesaid secondary heat exchanger, and with the output thereof connected to the open end of said first standpipe that is adjacent to the wall from which it extends; and

a cryogenic containe for housing the aforesaid primary and secondary heat exchangers and the first, second, and third self-contained container sections of said elongated container, with the internal chamber thereof connected for communication with that portion of the internal chamber of said vented first self-contained container section not occupied by said first and second standpipes, said wick, and said first liquid oxygen and for communication with the input of one of the heating passages of the aforesaid prim ary heat exchanger.

11. The container of claim 10, further characterized by: primary a water heater having a pump included therein for pumping heated water therethrough and therefrom, said water heater effecting the heating of said pumped water as a result of the oxidation of a fuel that leaves only solid products of combustion and requires no discharge of materials to said predetermined environment;

first open-ended pipe means communicating between that portion of said third self-contained container section not occupied by said second quantity of liquid oxygen and the cooling passage disposed therein and the input of the heating passage of said secondary heat exchanger;

second open-ended pipe means connected between the output of the heating passage of said secondary heat exchanger and the input of still another heating passage of said primary heat exchangers; and

a pressure controlled valve connected between the output of said another heating passage of said primary heat exchanger and the input of the combustion chamber of said water heater adapted for being opened in accordance with a preset pressure upstream of said pressure controlled valve.

12. The invention of claim 10, further characterized first opcn-cnded pipe connected between that portion of said third self-contained container section not occupied by said second quantity of liquid oxygen and the cooling passage disposed therein and the input of the cooling passage of said secondary heat exchanger;

means connected between the cooling passage output of said secondary heat exchanger, said predetermined environment. and the input of said second self-contained container section for dumping the exhaled gas from said secondary heat exchanger cooling passage thereto whenever the pressure difference between said cooled exhaled gas and said predetermined environment exceeds a given amount;

second open-ended pipe means connected between the output of said second self-contained container and the input of another heating passage of the aforesaid primary heat exchanger;

third open-ended pipe means connected between the heating passage output of said secondary heat exchanger and the input of another heating coil of said primary heat exchanger; and

a pressure relief valve located outside said cryogenic container and connected to the output of said another heating passage of the aforesaid primary heat exchanger for discharge of the non-rejuvenated gas stored in said second self-contained container section whenever the pressure thereof exceeds a predetermined pressure.

13. The invention of claim 10, further characterized by another pressure relief valve effectively connected between the output of the aforesaid conduit means and said predetermined environment for venting the exhaled gaseous breath from said conduit means thereto whenever the pressure thereof therein exceeds a predetermined amount.

14. The system of claim 10, further characterized by means effectively connected to said cryogenic container for effecting the refrigeration thereof to a cryogenic temperature.

15. The system of claim 1, wherein said pressurized predetermined make-up breathable gas comprises helium, and wherein said predetermined breathable, lifesustaining, gaseous mixture includes HeO 16. The system of claim 1, further characterized by a habitat, adapted for housing ordinarily air-breathing beings within a predetermined environmental medium, connected to the input-output of said respiratory means for effecting the life support of said ordinarily air-breathing beings housed therein. 

1. A system for supporting life in a predetermined environment, comprising in combination: respiratory meanS having a unitary input-output for receiving the exhaled breath of and for supplying a predetermined breathable, life-sustaining, gaseous mixture to an ordinarily air-breathing being, a downstream exhaled breath output, and an upstream inhalable gas input; a first check valve, adapted for free downstream flow, connected to the downstream exhaled breath output of said respiratory means; a first resilient, inflatable breathing bag having an input and an output, with the input thereof connected to the output of said first check valve; means connected to the output of said first resilient, inflatable breathing bag for removing carbon dioxide gas from the exhaled gaseous breath passing therethrough; means connected to the output of said carbon dioxide gas removing means for removing the moisture from the exhaled gaseous breath passing therethrough; means connected to the output of said moisture removing means for cooling the exhaled gaseous breath passing therethrough to the temperature of said predetermined environment; means effectively connected to the output of said carbon dioxide gas removing means for adding a predetermined quantity of gaseous oxygen to the exhaled gaseous breath passing therethrough at a predetermined partial pressure from a reservoir of liquid oxygen disposed within a cryogenic container; means connected to the output of said gaseous oxygen adding means for warming the gaseous breath to which said gaseous oxygen was added to a temperature which facilitates the breathing thereof by said ordinarily air-breathing being; a second resilient, inflatable, breathing bag having an input and an output, with the input thereof connected to the output of said oxygen-added gaseous breath warming means; a second check valve, adapted for allowing free downstream flow, connected between the output of said second resilient, inflatable bag and the upstream inhalable gas input of said respiratory means; a container of pressurized predetermined make-up breathable gas; a make-up control valve, adapted for being opened in proportional response to predetermined inflation conditions of said first breathing bag, connected between the output of said predetermined make-up breathable gas container and the input of the aforesaid carbon dioxide gas removing means; and a manually operable by-pass valve connected in parallel with said make-up control valve.
 2. The system of claim 1, wherein said respiratory means comprises a diver''s mouthpiece.
 3. The system of claim 1, wherein said respiratory means comprises a habitat for air-breathing beings disposed within said predetermined environment.
 4. The invention of claim 1, further characterized by: a controllable water heater having a pump incorporated therein in such manner as to pump heated water out the output thereof; a diver suit connected to and downstream of said controllable water heater in such manner as to be heated a predetermined amount by the pumped heated water therefrom; means connected to and downstream of said water heater for heating said carbon dioxide removing means a predetermined amount by the pumped heated water therefrom; means connected to and downstream of said water heater and pump for supplying a predetermined amount of heated water to said gaseous oxygen-added breath warming means for effecting the proper warming thereof; and an excess heat exchanger connected to and downstream of said water heater and pump for transferring excess heat in the pumped heated water to said predetermined environment.
 5. The invention of claim 1, further characterized by: a controllable water heater having a pump incorporated therein in such manner as to pump heated water and the output thereof; habitat means which enables human beings and other air-breathing mammals to live and perform useful functions in an otherwise unlivable environment connected to and downstream of said controllable water heater in such manner as to be Heated a predetermined amount by the pumped heated water therefrom; means connected to and downstream of said water heater and pump for heating said carbon dioxide removing means a predetermined amount by the pumped heated water therefrom; means connected to and downstream of said water heater and pump for supplying a predetermined amount of heated water to said gaseous oxygen-added breath warming means for effecting the proper warming thereof; and an excess heat exchanger connected to and downstream of said water heater and pump for transferring excess heat in the pumped heated water to said predetermined environment.
 6. The system of claim 1, wherein said means connected to the output of said carbon dioxide removing means for removing the moisture from the exhaled gaseous breath passing therethrough comprises a canister of dessicant.
 7. The system of claim 6 wherein the dessicant of said canister of dessicant comprises silica gel.
 8. The system of claim 1, wherein said means effectively connected to the downstream exhaled breath output of said respiratory means for removing carbon dioxide gas from the exhaled gaseous breath passing therethrough comprises a heatable carbon dioxide gas scrubber.
 9. The invention of claim 8, further characterized by means connected to said carbon dioxide gas scrubber for the heating thereof to a predetermined temperature.
 10. The system of claim 1, wherein said means effectively connected to the output of said carbon dioxide removing means for adding a predetermined quantity of gaseous oxygen to the exhaled gaseous breath passing therethrough at a predetermined partial pressure from a reservoir of liquid oxygen disposed within a cryogenic container comprises: a primary heat exchanger having a plurality of heating passages and a cooling passage; a secondary heat exchanger having a heating passage and a cooling passage, with the input of the cooling passage thereof connected to the output of the cooling passage of said primary heat exchanger; an elongated container having a first self-contained container section at one end thereof with a predetermined vent in the wall thereof, a second self-contained container section at the other end thereof, and a third self-contained container section located between said first and second self-contained container sections, said first, second, and third self-contained container sections being in heat sink configurations with each other, respectively; a first open-ended standpipe located within said first self-contained container section and extending a predetermined distance from the wall thereof that is opposite the vent thereof; a second standpipe located within said first self-contained container section, disposed around said first standpipe, and extending a greater distance from said wall than said first standpipe, said second standpipe having one end thereof closed by said wall and a plurality of apertures through the wall thereof in proximity with the other end thereof; a first quantity of liquid oxygen partially filling said first self-contained container section in such manner that it surrounds a predetermined length of said second standpipe without passing through a plurality of apertures through the wall thereof; a wick mounted on said second standpipe and dipsosed therearound in such manner as to be partially submersed in said first quantity of liquid oxygen; a second quantity of liquid oxygen partially filling said third self-contained container section; a cooling passage, having an input and an output, disposed within said second quantity of liquid oxygen, with the input thereof connected to the output of the cooling passage of the aforesaid secondary heat exchanger, and with the output thereof connected to the open end of said first standpipe that is adjacent to the wall from which it extends; and a cryogenic containe for housing the aforesaid primary and secondary heat exchangers and the first, second, and third self-contained container sections of said elongated container, with the internal chamber thereof connected for communication with that portion of the internal chamber of said vented first self-contained container section not occupied by said first and second standpipes, said wick, and said first liquid oxygen and for communication with the input of one of the heating passages of the aforesaid prim ary heat exchanger.
 11. The container of claim 10, further characterized by: primary a water heater having a pump included therein for pumping heated water therethrough and therefrom, said water heater effecting the heating of said pumped water as a result of the oxidation of a fuel that leaves only solid products of combustion and requires no discharge of materials to said predetermined environment; first open-ended pipe means communicating between that portion of said third self-contained container section not occupied by said second quantity of liquid oxygen and the cooling passage disposed therein and the input of the heating passage of said secondary heat exchanger; second open-ended pipe means connected between the output of the heating passage of said secondary heat exchanger and the input of still another heating passage of said primary heat exchangers; and a pressure controlled valve connected between the output of said another heating passage of said primary heat exchanger and the input of the combustion chamber of said water heater adapted for being opened in accordance with a preset pressure upstream of said pressure controlled valve.
 12. The invention of claim 10, further characterized by: first open-ended pipe connected between that portion of said third self-contained container section not occupied by said second quantity of liquid oxygen and the cooling passage disposed therein and the input of the cooling passage of said secondary heat exchanger; means connected between the cooling passage output of said secondary heat exchanger, said predetermined environment, and the input of said second self-contained container section for dumping the exhaled gas from said secondary heat exchanger cooling passage thereto whenever the pressure difference between said cooled exhaled gas and said predetermined environment exceeds a given amount; second open-ended pipe means connected between the output of said second self-contained container and the input of another heating passage of the aforesaid primary heat exchanger; third open-ended pipe means connected between the heating passage output of said secondary heat exchanger and the input of another heating coil of said primary heat exchanger; and a pressure relief valve located outside said cryogenic container and connected to the output of said another heating passage of the aforesaid primary heat exchanger for discharge of the non-rejuvenated gas stored in said second self-contained container section whenever the pressure thereof exceeds a predetermined pressure.
 13. The invention of claim 10, further characterized by another pressure relief valve effectively connected between the output of the aforesaid conduit means and said predetermined environment for venting the exhaled gaseous breath from said conduit means thereto whenever the pressure thereof therein exceeds a predetermined amount.
 14. The system of claim 10, further characterized by means effectively connected to said cryogenic container for effecting the refrigeration thereof to a cryogenic temperature.
 15. The system of claim 1, wherein said pressurized predetermined make-up breathable gas comprises helium, and wherein said predetermined breathable, life-sustaining, gaseous mixture includes HeO2.
 16. The system of claim 1, further characterized by a habitat, adapted for housing ordinarily air-breathing beings within a predetermined environmental medium, connected to the input-output of said respiratory means for effecting the life support of said ordinarily air-breathing beings housed theRein. 